Quote:
Originally Posted by
illnastyimpreza /forum/post/12947230
^ verry informative post. I had been under the interpretation that tubes where better in all ways...
I will have to change my thinking
I still wonder why Vacume Tube car amplifier are so much more money....
Probably the same reason we pay $300 or more for our projection bulbs. The market is small and most manufacturers of tubes went out of that business. It is now a very small market for the types used in audio equipment.
Vacuum tube home amplifiers also cost a lot more today but they used to be very affordable if not cheaper than transistor amplifiers. I think McIntosh was one of the last big holdouts making lots of tube amps, and that was partly because they were very reliable and therefore widely used for pa systems as well as audio systems.
There are some inherent added design costs too with tubes. One that comes to mind is you need a very clean extra filtered DC for the filaments. If you don't you will get audible noise or hum. I remember they used to make EEG machines for hospitals that were using tubes and the preamp stages were run off a 12 volt battery because of this. In a car alternators add noise too.
Filaments are just an added path for it to get into the sound.
Tubes generate lots of heat too. People complain here regularly about their Onkyo running too hot because it feels warm to the touch. With tubes you will get burned if you touch one for 1/2 second, while it is on.
Finally car audio is kind of a problem due to the 6 or 12 volt car batteries. It is even harder to get tubes to work at those voltages. House line voltages are much more friendly. Tubes are suited for high voltages and low currents, the opposite of most transistors. So generally at least for 6 volts they used some means to step up the voltages. That is why most tube amps need output transformers and transistor ones don't.